460 research outputs found
Superstatistics from a different perspective
In this paper we elaborate on the recently proposed superstatistics formalism
[C. Beck and E.G.D. Cohen, Physica A 322, 267 (2003)], used to interpret
unconventional statistics. Their interpretation is that unconventional
statistics in dynamical systems arise as weighted averages of the ordinary
statistics obeyed by these systems over a statistical distribution of
background configurations due to fluctuations intrinsic to the background. In
this paper we suggest that the same picture can arise because of the intrinsic
dynamics of the system. The dynamics of the system and the background, hence,
concur together to determine the overall final statistics: differently evolving
systems embedded within the same background can yield different statistical
distributions. Some simple examples are provided; among them a toy model able
to yield a power-law distribution. Also, some recent independent results are
quoted, that appear to support this viewpoint.Comment: 10 pages. Final version to appear in Physica
Further study of the Over-Barrier Model to compute charge exchange processes
In this paper we study theoretically the process of electron capture between
one-optical-electron atoms (e.g. hydrogenlike or alkali atoms) and ions at
low-to-medium impact velocities () working on a modification
of an already developed classical In this work we present an improvement over
the Over Barrier Model (OBM) described in a recent paper [F. Sattin, Phys. Rev.
A {\bf 62}, 042711 (2000)]. We show that: i) one of the two free parameters
there introduced actually comes out consistently from the starting assumptions
underlying the model; ii) the modified model thus obtained is as much accurate
as the former one. Furthermore, we show that OBMs are able to accurately
predict some recent results of state selective electron capture, at odds with
what previously supposed.Comment: RevTeX, 7 pages, 4 eps figures. To appear in Physical Review A
(2001-september issue
Chaos in coplanar classical collisions with particles interacting through forces
The scattering among three particles interacting through forces, with
opposite charges and widely different masses, is studied in a coplanar
geometry. The present work shows that at low impact velocities the output of
the collision presents typical fingerprints of chaos. The details of the
process are investigated.Comment: ReVTeX (uses epsf), 8 pages, 5 figs. To be published as a Brief
Report in Phys. Rev.
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